Timing mark – harmonic balancer – engine 472

[Ragnar]

Does anyone have a picture of the timing mark on the harmonic balancer for the 472 engine? The car in question is a 1972 Coupe de Ville, but the mark might be the same on other model years.

[TJ Hopland]

I don't have a 72 or 72 manual so can't help.  I am curious why you are asking?  Is it missing or just too dirty to read? 

Any signs or clues that anything has been changed on this thing?  Over the years 68-81(ish) of that engine family they had slightly different pulleys and gauges that don't quite interchange so ideally if you were to change the pulley you also wanted the gauge that came with it originally.  A common reason to swap these around is to eliminate the 'smog' pump.  The smog pump cars which was most of them most years the smog belt ran over the crank and water pump then the alternator belt just ran to the water pump so no smog no alternator. 

Some years like 70, 75, 78 there were some that didn't have the smog pumps so people often swap to those years to simplify things a bit.  There was also the change from the dual AC/PS belt to the fatter single that happened around 74 that appeared to be done mostly to gain clearance around the larger HEI distributor cap so another reason someone could have been messing with belts and pulleys.

The people that knew what they were doing either buyers or sellers would deal in a 3 piece set, crank pulley, water pump pulley, and the timing gauge.  IF you were really on top of it and up for more work also the lower alternator bracket because on the smog engines it extended down to support the smog pump.  Can't hardly see that when its in a car so I don't think a lot of people really worried about it.  If you are not dealing with a matched set you can have odd issues with belt alignment, pulley rubbing, and timing not making sense. 

If you can post some pics of what you are working with perhaps some of us could offer our best guess if you are dealing with a stock 72 engine or something else.  At this age just about anything could have happened to this thing.  Not all that long ago we had a person with I think a 69 and a lot of things just were not making sense but the valve covers caught my eye as not seeming quite right so we dug a little deeper and found out at some point someone swapped in a 368. Likely just what was available at the time someone needed an engine for the thing.  Ya never know sometimes even if its been in the family.  Maybe Uncle Gus never told Gradpa Joe what happened when he got to use the car on prom night all those years ago......

[Ragnar]

I am new to adjusting the timing. I am curious what to look for. I wish I was closer to having the exact reference.

Can it be this. I market it to get a better read without any improvments

https://share.icloud.com/photos/053-NFtoRTHyhk7vOJuXXkjrw

[Clewisiii]

Here is his picture.

[TJ Hopland]

I don't remember it being a V on the pulley but its not the kind of thing I likely have had to think to hard about.  Usually it was more of a line.   Is there any other marks on the pulley?  If not then that has to be it.   

Are you just checking the timing to check it or are you having some sort of issue?  You say you are new to checking timing?  I assume you have a timing light?   One thing that gets people with these engines is unlike many other American V8's the #1 cylinder on these is on the passenger side.  A downside to this setup is you need to be standing and pointing the light on the drivers side so take some time to make sure the wires for your light are routed out of the way of the fan and belts. 

Once you have the light connected to #1 wire start er up and point the light down at the pulley and the light should flash when #1 sparks and this creates a sort of freeze frame view of the pulley and where that mark lines up with the gauge is in theory the timing. If the car is running decent(ish) I would not just adjust it just yet.  Let us know what your concerns are and we cam maybe lead you to some other checks.

If this is a stock 72 distributor its gonna still have 'points' which are mechanical contacts inside the distributor that are what actually triggers the spark to happen.  There are conversion kits that can eliminate them and in 75 factory went to the HEI which was an electronic trigger.  The HEI fits in the older engine so it was a common upgrade for some people.  The points style has the ignition coil laying sideways near the distributor with a plug wire leading to the distributor.  The HEI has the coil in the middle of the much larger cap. 

With points to do a proper test/tune up you also need what is usually called a dwell/tach meter.  Much like timing lights you can usually find them used often times sill in the box that were maybe used one time back in the 80's.  You use the meter set to dwell mode and there is a spec for and on the GM V8's can easily be adjusted via that little hatch in the bottom of the distributor cap. You also want to rev the engine while observing the dwell reading and make sure the needle is staying fairly steady.  If its jumping around the points are sticky and or the distributor shaft is worn.

Once you have the dwell dialed in you can check the timing.  Again if its running decent and the timing isn't to spec I would not panic and change it.  If you do change it be sure you take notes as to where it was before you started.  Sometimes for one reason or another the marks just don't align so it would be nice to know where you started just in case setting it 'right' makes it worse. 

You also ideally want to have a hand vacuum pump/gauge to check the vacuum advance.

Let us know if you have more questions and pics are always helpful. If you have the pics on the device you are posting with you can load them direct into the site, no need for the links.

Oh ya and at least from that one photo it looks like you have the dual belt smog setup which would be stock for 72.   

[Ragnar]

I've got an HEI, but I don't have the tools to measure dwell, only simple timing lamp and a tachometer. I connected the vacuum advance directly to a manifold port, so I'll unplug that and see if I can get a reading.

I suspect the mixture is too rich, since the last time I checked the timing it hit 0 degrees with vacuum connected.

So I'm only talking about a small adjustment.

[TJ Hopland]

You only need dwell meter for a points system. There is still a dwell component you can read with an electronic system like HEI but you can't adjust it, its built into the electronics.

Timing is zero with the vacuum connected?  I would keep exploring things before making any adjustments.  You are for sure connected to the #1 wire which is the front one on the passenger side?  Try to connect closer to the spark plug and try to keep the probe away from other plug wires.  Many of the probes are bad about picking up signals from nearby wires especially if you are clamping on near the distributor.  I just want to be sure you are getting a clean signal off #1.

I was trying to remember what the firing order was on these and did a search and 8 out of 10 results were wrong.  That always used to be a problem but AI seems to have made it worse and look more convincing. 

A hand vacuum pump and gauge is the best way to check the vacuum advance because you can easily control the vacuum and compare those readings to the manual.  Since you got an HEI there is very little chance its actually the official correct curves for an otherwise stock 72 but it would be nice to see what its doing to make sure its not crazy.  The vast majority of the replacement vacuum canisters for the HEIs have way too much advance in them so what usually happens is you end up with detonation (pinging) and the 'fix' is just to retard the whole distributor which then causes other issues.  The real fix is to try and get the proper can or get one that has the limiting cam you can set to a reasonable range.

The HEI's are also prone to having the weights and stuff bind up so you should also rev the engine with the vacuum unhooked and make sure the mechanical advance is working and reasonable.   If your timing light doesn't have a tach function this is where the dwell tach meter comes in handy again you can use the tach function to see where the advance is coming in.

If your timing light doesn't have the dialback function and you need more range to see what the timing is doing you can measure on the timing gauge the distance from 0 to 10 and then make additional marks on the pulley with that spacing so depending on which mark is near the gauge you add 10 to the reading so if its at 4 on the new first 10 mark its 14.  A dial back light is much easier but making additional marks works too. 


What carb is on this thing?  And what indications are you getting that its rich? 

[Ragnar]

Thx for all your imput. I'll check the top Center and come back to you. Thank you for all this great info.

[TJ Hopland]

What are the symptoms that make you think its rich?


To really check top dead center accurate enough to tell if your timing marks are correct you need a piston stop and to know how to use one.  A piston stop is basically a bolt that goes into the spark plug hole and basically hits the top of the piston. 

You set the stop so it hits the piston just before it gets to top dead center.  You then gently rotate the crank and bump into the stop.  You then make a mark on the pulley.  Next you rotate the crank the other direction till it hits the stop again.  Make another mark.  Now measure the distance between the two marks you made.  Center point is TDC. 

You can't just eyeball it because of geometry there is a dwell time where the crank is moving but the piston isn't as it passes past that zero point so if you are gonna do it to be sure you got to do it.  If you are not able or prepared to go through the whole process you might as well not know and just go with what seems to work. 

[Ragnar]

I'll put my finger on cylinder #1 to verify compression.

The engine is running rich — fuel consumption is high, plugs are fouled black, and it leaves black marks on the asphalt under throttle. Choke operation appears normal.

https://share.icloud.com/photos/059EGiWAjrjGQ1ecGY7WGJyEw

[Ragnar]

I haven't checked the distributor against top dead center yet, but I discovered something valuable thanks to you. I was measuring timing off the wrong cylinder. That gave me the chance to verify the firing order, and it is correct.

Timing without vacuum is at 12/13°.

Manifold vacuum is pulling 15/16 in-Hg at around 650 rpm.

So that's where I'm at right now.

I'm not sure what type of distributor I have.

[TJ Hopland]

Is the oil on some of those plugs from some external leak or source like penetrating lubricant you applied to remove them?  How much has this engine run or been driven since its been in your care and have you replaced the plugs?   I want to know if those nasty plugs are just because it had sat a long time and perhaps engine was stuck so someone put something down the cylinders to free it up and maybe now that its running rings are still a little stuck?

Reason I'm thinking / hoping for the sitting and a bit sticky theory is if this was a Chev engine I would say chances are good its just whipped and done but being a Cadillac it really takes a lot of use and abuse to whip one.  It can certainly happen especially as time passes an more owners are involved but even today its not that common to see so that's why I'm not yet jumping to that conclusion.   

How about some general underhood pics like with the air housing off?  Maybe we can get an idea if you are dealing with a fairly stock setup or if you got a really mixed and modded mess going on.
 

Ok, sounds like when you said TDC you meant confirming TDC(ish) AND compression stroke.  If its running that's not gonna be off but I will mention the process anyway incase you need it later or someone else has issues and finds this thread in the future.  

Where you usually get into that is if its not running or if the distributor has been removed.  On this engine #1 (passenger side) and #4 (drivers side) is the pair so both are at TDC when the timing marks line up but only one of them is going to have the valves closed and ready for spark and with the valve covers installed thumb over the spark plug hole is a valid way to determine which one is doing which.

I use #4 for this test because I can stand on the drivers side of the engine and see the timing marks with my thumb over the hole while someone else bumps the starter.  If you are using #4 you then just make sure the rotor is then pointing at the terminal that the #4 wire is connected to assuming that when the marks aligned the pressure was blowing your finger on the #4 hole. 

Don't get too hung up on where on the cap that wire is.  All that really matters is that the rotor is pointing to the terminal with the wire that goes to the cylinder that just had the pressure on your finger and they are all in the correct order.  Some engines from the factory the rotor actually points to a cylinder so people get hung up on that and even those it didn't have to be that way.     

[Ragnar]

I changed the plugs after I took that picture, so I'll get a few more photos.

It could be WD-40, as you mentioned.
We'll see.

I've had the car for 20 years, but it hasn't been driven in 15.
My granddad bought it new, though there were a few other owners during a 35-year gap.

It's pretty much stock, came with a '71 carb.

The car was assembled in Switzerland.

[TJ Hopland]

Cool that there is some history with this car. I had read about GM's world assembly plants before where they basically shipped over a kit to be assembled.  I'm sure it had to do with various rules and regs and fees.  Guessing a Cadillac would have been pretty rare to have been done that way.  I would guess a Cadillac buyer would have been able to afford the extra fees so they could import a whole car and it was mostly makes and models where the pricing was trying to be more competitive that were done that way.   

Where (roughly) are you and the car now?  If you are outside the USA that could chance some recommendations we would make sine availability could be different in different countries.

[Ragnar]

Norway.

[Ragnar]

[Roger Zimmermann]

It's pretty much stock, came with a '71 carb.

The car was assembled in Switzerland.

No way the car was assembled in Switzerland. There were just 24 Cadillac assembled in Bienne: 12 in 1938, 6 in 1939 and again 6 in 1940.
The last US car brand assembled in Switzerland was Chevrolet, the year was 1968. The assembly plant closed in 1975.

[Ragnar]

No way the car was assembled in Switzerland. There were just 24 Cadillac assembled in Bienne: 12 in 1938, 6 in 1939 and again 6 in 1940.
The last US car brand assembled in Switzerland was Chevrolet, the year was 1968. The assembly plant closed in 1975.

GENERAL MOTORS SUISSE S.A. BIENNE
→ Indicates that the car was assembled in Switzerland (CKD kit – "completely knocked down" from the USA, then assembled locally).

🔹 MAKE: CADILLAC
→ The brand is Cadillac.

🔹 MODEL: 2 DEVILLE 68347 A REL
   •   "2 DeVille" → Series/body style variant, DeVille.
   •   68347 → Cadillac body code:
   •   68 = Cadillac DeVille series
   •   34 = 2-door hardtop coupe
   •   7 = DeVille (not Calais or Eldorado)
→ This means a 1972 Cadillac Coupe DeVille.
   •   "A REL" → From French "à reluire" or "assemblé," meaning it was assembled/painted locally in Bienne.

🔹 MOTOR: R
→ Engine code. "R" stands for the 472 CID V8 (345 hp SAE gross, 220 hp net in 1972).

🔹 CHASSIS: 6D47R2Q136493
This is the VIN/chassis number. Let's decode it:
   •   6 = Cadillac division
   •   D = DeVille series
   •   47 = 2-door hardtop coupe
   •   R = 472 CID V8 engine
   •   2 = Model year 1972
   •   Q = Assembly plant (here "Detroit, Hamtramck" – but the car was shipped as a kit to Switzerland)
   •   136493 = Production sequence number

[Clewisiii]

Side note, I was working with the head of  GM archives on looking up the build sheet for a 1952. He said this was the first time he had seen two build sheets for one car.

The car was shipped to Europe in primer and finished there. Looking at the bottom of the second sheet it shows 4 possible engine number combinations. The invoice weight only looks like one car. So I am not sure how that worked out.

[Carfreak]

Side note, I was working with the head of  GM archives on looking up the build sheet for a 1952. He said this was the first time he had seen two build sheets for one car.

My 1939 Limo has 'many' pages. Trying to get more clear copies but there are up to 10 pages defining the build, customer provided equipment, special transport to Federal Laboratories, return to Detroit and ultimate delivery by private rail car to Wash DC.